Molarity Calculator

About this tool

Calculate the molarity of a solution from mass, molar mass, and volume — or flip it around to find exactly how much solute (in grams) you need to reach a target molarity, using the standard formula M = moles ÷ liters.

Frequently asked questions

What is molarity?

Molarity (M) measures solution concentration as moles of solute per liter of solution — one of the most common ways concentration is expressed in chemistry.

How is moles calculated from mass?

Moles = mass (g) ÷ molar mass (g/mol). The molar mass is specific to each compound (for example, NaCl is about 58.44 g/mol).

Does this account for solution volume changes when dissolving a solid?

No — it assumes the stated volume is the final total solution volume, which is how molarity is defined and typically prepared in a lab (dissolve, then bring to volume).